The crankshaft and connecting rods of an internal combustion engine have various bearing surfaces that require lubrication. Such bearing surfaces are lubricated by moving oil around in a crankcase. The oil is typically moved by using an oil pump to transfer the oil through flow channels. However, for practical purposes, the design of the oil pump should be as simple as possible to minimize costs and maintenance.
In particular, for small utility engines that are used for such applications as lawn mowers and other yard appliances, elaborately designed oil pumps would undesirably increase the complexity of the engine design, the cost of manufacture, and the necessary maintenance. Therefore, provision of a simple, easy to manufacture oil pump having minimal moving parts is a desired goal of this small utility engine market. One objective of this invention is to provide such an oil pump.